Human Papillomavirus negative but dyskaryotic cervical cytology: re-analysis of molecular testing

Evaluation of molecular Human Papillomavirus (HPV) testing into UK Cervical Screening Programmes is underway. In South Wales the current HPV prevalence in women attending routine screening is 13.5% with 76.3% HR HPV positive in cases with reported dyskaryotic cervical cytology [Hibbitts S, Jones J, Powell N, Dallimore N, McRea J, Beer H, et al. Human papillomavirus prevalence in women attending routine cervical screening in South Wales, UK: a cross-sectional study. Br J Cancer 2008;99(December (11)):1929-33].

The aim of this study was to re-analyse the 23.7% cases with reported dyskaryotic cytology that were HR HPV negative (n=52 out of 219 in a population of 10,000).

Three procedures were performed: (i) GP5+/GP6+ PCR-EIA repeat on original DNA extracts; (ii) DNA extraction and GP5+/GP6+ HPV PCR-EIA; (iii) DNA extraction and HPV typing using Greiner Bio-One PapilloCheck DNA microarray.

51 out of 52 samples were re-analysed. Direct repeat HPV PCR-EIA identified 24% (n=12/51) of samples positive for HR HPV. Re-extracted DNA and PCR-EIA increased detection to 41.2% (n=21/51) and PapilloCheck detected 78.4% (n=40/51). HR HPV detection by PapilloCheck was significantly higher compared with the other methods of re-analysis. Eleven samples were persistently HR HPV negative but 4 tested positive for low risk HPV.

This study identifies that up to 78% of samples with dyskaryotic cervical cytology that test negative for HPV can be found to be HPV positive on re-analysis. The reliance on a single negative HPV test result could lead to missed HPV related disease in a subset of patients, the number dependant on which HPV test is performed. The clinical significance of a false negative HPV result depends on the screening interval and how HPV testing is incorporated into screening.